I-Da Choi has life pretty rough, being forced since a young age to be a slave to the daughter of her parent's boss, Mi-Mi. So in order to relieve stress, she dresses up as a boy, Yo-Dah, and goes around calling up gangs so she can beat the shit out of them. Along the way, she makes two friends, Ju-Nah and Shi-Nah, neither of whom mind him keeping his background secret, especially since they've got a few secrets of their own. Then one day, she gets kissed by a complete stranger as I-Da in order to fool said stranger's clingy girlfriend. When she later pays the stranger back, as Yo-Dah, he mistakes her for his dead little brother, Mi-Ru. The next day he starts showing up at her school looking for Choi Yo-Dah, and so a complicated drama commences.
This series provides examples of:
- Aborted Arc: It seemed like Nu-Na was going to play a bigger role, but Ju-Nah very quickly takes care of her and she's hardly heard of again.
- Attempted Rape: Early on, several thugs try this on Mi-Mi, but quit after their boss falls in love with her. Near the end, Mi-Mi has those same thugs, with her new boyfriend's help, do the same thing to I-Da. They almost succeed, and were only stopped by the untimely intervention of Na-Ru.
- Batman Gambit: Na-Ru's grandfather pulls one to try and keep Na-Ru and I-Da apart. It ends up falling through thanks to his secretary, and he accepts the situation very quickly.
- Bifauxnen: I-Da makes an effeminate but effective boy, in order to vent the frustrations of being under the thumb of Mi-mi. As Choi Yodah, she accidentally attracts a female bully after rescuing her and a Bishounen named Na-ru because she resembles his dead little brother. If Ida's so poor and her room so small, where did she get and stash all those flashy male clothes? And where did she get them to begin with, or is Asian fashion that androgynous?
- Bully Hunter: Yo-Dah. Shi-Nah even lampshades it after Yo-Dah threatens to beat him up after catching Shi-Nah stalking him.
- Clingy Jealous Girl: Mi-Mi, who crosses the
Moral Event Horizon in order to get revenge on Na-Ru for dumping her. Also Nu-Na and an unnamed girlfriend of Na-Ru, but they aren't as bad just because they have much, much less screentime. - Defeat Means Friendship: The finale shows that I-Da and the trio have become good friends.
- Despair Event Horizon: Mi-Mi pretty much breaks after she comes home after being humiliated by her boyfriend, classmates, and maid to see her father being arrested for his shady deals and realizing that Shi-Nah's finally gone through with what he's been threating to do half the series and turned her father in. Which means that essentially, she will have the same fate as I-Da: going from having everything to having nothing. She ends up becoming a shut-in in her uncle's house, refusing to see or talking to anyone. You still can't feel sorry for her, though.
- Dissonant Serenity: Hok-Yoon hardly even stops smiling, not even when he realizes that Mi-Mi had been using him all along.
- Earn Your Happy Ending: I-Da has to go through a whole lot in order to get to the finale.
- The Glasses Come Off: When I-Da is Yo-Dah. After she's outed, she takes the glasses off permanently.
- Her Heart Will Go On: Subverted. Believing that Na-Ru had pulled an Heroic Sacrifice for her in the finale, I-Da had decided to never fall for anyone else again... but it turned out that Na-Ru had survived (though barely) and she and Shi-Nah had been lied to.
- Humiliation Conga: In the finale, Mi-Mi gets one so bad that she ends up becoming a shut-in, refusing to interact with anyone. Still can't feel sorry for her, though. (Though in the very end, I-Da does.)
- Important Haircut: I-Da lets her hair down after the Jerkass Has Apoint moment, showing everybody that she isn't going to take their crap anymore.
- Jerkass Has a Point: An unintentional example. After Mi-Mi outs I-Da to the whole class, the leader of the trio crushes I-Da's glasses, saying she doesn't need them. I-Da takes the advice to heart, beats up the classmates who were teasing her, lets down her hair, tells everyone that she's not going to pretend to be somebody she isn't anymore, and that she'll beat the ever-loving crap out of anybody who tries to make her be anything else.
- Kick the Dog: While Na-Ru is a nice guy, he does some pretty ass-holish things, like abandoning Mi-Mi to be raped by a gang and dumping I-Da and trying to leave the country after he finds out about her true identity.
- Laser-Guided Karma: Works for both sides. Mi-Mi ends up getting all the crap she inflicted on I-Da and then some, and it's implied that it just gets worse, while I-Da becomes completely free of debt, her parents love her again, she doesn't have to deal with any of the bullies anymore, and gets the guy in the end.
- Loves My Alter Ego: Pretty much the premise of the entire series is I-Da worrying that Na-Ru will hate her if he finds out she's a girl. Also, the leader of the trio falls for Yo-Dah, and is understandably miffed when he: 1. dumps her for Na-Ru, and 2. turns out to be a girl.
- Manipulative Bitch: Mi-Mi, due to her use of the Wounded Gazelle Gambit, is an even worse bully than Sae.
- The Matchmaker: Gang's secretary ships I-Da and Na-Ru, but tries to get Shi-Nah and I-Da together. After Shi-Nah refuses to go through with her plan, she decides to defy her boss and get I-Da and Na-Ru together.
- Nice Job Fixing It, Villain: The leader of the Girl Posse breaks I-Da's glasses, intending to break her - instead, I-Da listens to her advice and takes it to heart, and decides not to put up with everybody's crap anymore.
- Rich Bitch: Every rich woman in the series, but Mi-Mi takes the cake.
- Scars Are Forever: Hak-Yoon's revenge includes burning Mi-Mi on the forehead with a cigarette so that he'll be able to find her once he's out of juvenile hall. Everybody says afterward that you can't get rid of burns like that.
- Spanner in the Works: Na-Ru's grandfather's secretary, who ultimately undoes the plan of Na-Ru's grandpa to keep I-Da and Na-Ru apart, alongside some help of Shi-Nah.
